This invention relates to a method of and an apparatus for splicing spun yarns.
A method is conventionally employed wherein end portions of yarns overlapped one on the other are acted upon by a compressed fluid in order to splice such yarn ends to each other.
In an apparatus which employs such yarn splicing technique, such as an apparatus disclosed in a U.S. Pat. No. 4,002,012, two yarn ends are inserted into a yarn splicing hole so as to be directed in opposite directions to each other and compressed air is injected into the yarn splicing hold to oscillate or turn the overlapping portions of the yarn ends, thereby interlacing yarn end portions with each other to effect splicing of the yarns. In this apparatus, if overlapping portions of the yarn ends are both clamped at two respective different positions thereof and segments of a particular dimension of the overlapping portions of the two yarns which are thus arrested within a particular section are turned, then fibers of the yarn end segments between the clamped points thereof will be enveloped to one another by temporary twisting, the attaining intended splicing of the yarns. In such yarn splicing, however, extremities of the yarns outside the clamped portions extend from the opposite ends of the clamped portions and will remain as antennae to the yarns thus spliced. Such antennae may possibly be caught by a knitting needle in a subsequent knitting step to cause breakage of the yarn, thereby deteriorating the quality of a product such as a fabric and textiles.
Also, according to the apparatus as described above, fibers around a spliced joint may partially be coiled around each other in an opposite direction to the direction of twisting peculiar to the yarns and thus run in parallel relationship. As a result, the spliced joint of the yarns will not present sufficient strength nor sufficient thickness. In particular, if substantially the center between the overlapping portions of the ends of both yarns is acted upon by an injected turning air flow in a direction, then the overlapping portions are ballooned and the yarn ends on opposite sides of the acting point of the compressed air are twisted in opposite directions to each other so that one of the yarn ends is provided with a twist in the same direction to the twisting direction peculiar to the one yarn while the other yarn is provided with a twist in the opposite direction to the twisting direction peculiar to the other yarn. Accordingly, one portion of the spliced joint will be increased in strength while the other portion of the spliced joint will be reduced in strength, and since the maximum value of tensile strength of the spliced joint is determined by the weakest portion of the spliced joint, the entire spliced joint will have such a reduced strength.